Ethereum Classic (ETC) Hit by Double-Spend Attack Worth $1.1 Million

Popular cryptocurrency exchange Coinbase has suspended all transactions of Ethereum Classic (ETC)—the original unforked version of the Ethereum network—on their trading platforms, other products and services after detecting a potential attack on the cryptocurrency network that let someone spend the same digital coins twice. Why is this attack concerning? The heist resulted in the loss of $1.1